It's mostly the euro zone debt crisis, but they also cite the failure of US and Japan to containt their own debt problems.

Reuters:

In a report sharply cutting its world economic growth expectations, the World Bank said Europe was probably already in recession. If the euro area debt crisis deepened, global economic forecasts would be significantly lower.

"The sovereign debt crisis in the euro zone appears to be contained," Justin Lin, the chief economist for the World Bank, told reporters in Beijing on Wednesday.

"However, the risk of a global freezing-up of the markets and as well as a global crisis similar to what happened in September 2008 are real."

The World Bank predicted world economic growth of 2.5 percent in 2012 and 3.1 percent in 2013, well below the 3.6 percent growth for each year projected in June.

"We think it is now important to think through not only slower growth but sharp deteriorations, as a prudent measure," said Hans Timmer, director of development prospects at the bank.

The World Bank said if the euro area debt crisis escalates, global growth would be about 4 percentage points lower.

It forecast high-income economies would expand just 1.4 percent in 2012 as the euro area shrinks 0.3 percent, sharp downward revisions from growth forecasts last June of 2.7 percent and 1.8 percent, respectively.

It cut its forecast for growth in developing economies to 5.4 percent for 2012 from its previous forecast of 6.2 percent, saying expansion in Brazil and India and to a lesser extent Russia, South Africa and Turkey, had slowed already.

Is Europe's debt crisis "contained?" If the EU manages to come to an agreement to form a fiscal union, and if Greece can get together with their private creditors to agree on the bond haircut they must take, and if there are no more credit downgrades, and if the bailout mechanism, the EFSF, can attract enough cash to intervene successfully in a crisis, and if France and Germany can lead the EU out of this mess they've created, then yes - the crisis has been "contained."

Otherwise, not so much.